The present invention relates to a method of creating a storm drain and/or sewer with a plurality of precast concrete box culverts. In addition, the present invention relates to a box culvert and gasket assembly capable of use in forming fluid-tight bell-and-spigot-joints.
Precast concrete box culverts are used to form relatively-large underground storm drains and sewers. A plurality of separately manufactured box culverts can be coupled together end-to-end at a job site to form a desired run of a storm drain or sewer. As noted by the term “box”, box culverts are typically rectangular and define a relatively-large substantially-rectangular passageway therethrough that extends between opposite end faces of the box culvert. For example, the end face of a box culvert may have a 12.5 foot span by a 4 foot rise, or may be of other rectangular dimensions such as a 5 foot span by a 3 foot rise. Each box culvert and its defined passage may have a length of about several feet. The precise alignment and proper coupling of box culverts at a job site is difficult due to the bulky size and substantial weight of the box culverts. Accordingly, progress of the construction of a storm drain or sewer can be limited to coupling as few as about three box culverts per day.
One end face of a precast concrete box culvert typically has a spigot that is substantially rectangular in end elevation. The spigot has four generally straight sides interconnected by four right angle corners. The opposite end face of the box culvert has a complementary-shaped bell for receiving the spigot so that adjacent box culverts can be coupled together to form a bell-and-spigot joint therebetween. Gaskets or the like can be compressed within the joint to provide a fluid-tight seal. Typically, four separate rubber gaskets are mounted on the spigot, one on each side of the rectangular spigot. The ends of the rubber gaskets are cut at a 45° angle so that they abut with an end of an adjacent gasket at the right angle corner. Seals with such gaskets have met certain industry standards which require a seal to be leakproof only up to about 6 psi.
U.S. Pat. No. 6,827,326 B2 issued to Giri provides an example of a precast concrete box culvert capable of forming a bell-and-spigot-joint. Also see U.S. Pat. No. 5,169,161 issued to Jones and U.S. Pat. Nos. 5,482,403 and 5,525,007 issued to Jones et al. which disclose bell-and-spigot-joints in general and gaskets for cylindrical pipes.
While the box culverts, gaskets, and joints disclosed above and in the above referenced patents may function in an acceptable manner, there is a need for an improved box culvert and gasket assembly, an improved watertight storm drain and/or sewer made from box culverts, and an improved method of forming a fluid-tight seal between box culverts. Preferably, the assembly should provide a seal that can compensate for any misalignment between adjacent box culverts, should enable ready coupling of box culverts thereby reducing the construction time of storm drains and sewers, and should create a seal capable of remaining fluid-tight up to at least 13 psi of water pressure.